package cn.com.connected.base.utils;

/**
 * @program: letter-server
 * @description:
 * @author: 邵明生
 * @create: 2019-04-16 00:50
 **/
public class SamewayUtil {
    private static double EARTH_RADIUS = 6378.137;
    /**
     * 作者:   邵明生
     * 时间:   2019/4/16 0:50
     * 描述:   计算路线倾斜角度  (目前仅支持国内)
     */
    public static double getAngle(double lat_a, double lng_a, double lat_b, double lng_b) {
        double y = Math.sin(lng_b-lng_a) * Math.cos(lat_b);
        double x = Math.cos(lat_a)*Math.sin(lat_b) - Math.sin(lat_a)*Math.cos(lat_b)*Math.cos(lng_b-lng_a);
        double bearing = Math.atan2(y, x);
        bearing = Math.toDegrees(bearing);
        if(bearing < 0){
            bearing = bearing +360;
        }
        return bearing;
    }

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    /**
     * 通过经纬度获取距离(单位：米)
     *
     * @param lat1
     * @param lng1
     * @param lat2
     * @param lng2
     * @return 距离
     */
    public static Double getDistance(double lat1, double lng1, double lat2,
                                     double lng2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
                + Math.cos(radLat1) * Math.cos(radLat2)
                * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000d) / 10000d;
        s = s * 1000;
        return s;
    }
}
